GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1999 🢒 Park Avenue 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Twilight Sentinel Inoperative

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check?

--

Go to Step 2

Go to Headlight System Check

2
  1. Disconnect the Lamp Control Module (LCM) connector C2.
  2. Turn the ignition switch to the RUN position.
  3. Connect a DMM from the LCM connector C2 cavity A7 (PNK) to ground.

Is the voltage within the specified range?

10-15 V

Go to Step 3

Go to Step 7

3
  1. Connect a DMM from the LCM connector C2 cavity A6 (PPL) to ground.
  2. Vary the twilight delay control from MIN to MAX.

Does the resistance vary within the specified range?

3.5K ohms-200K ohms

Go to Step 4

Go to Step 8

4
  1. Cover the ambient light sensor.
  2. Connect a DMM from the LCM connector C2 cavity A5 (WHT) to ground.

Is the resistance greater than the specified value?

31K ohms

Go to Step 5

Go to Step 11

5
  1. Expose the ambient light sensor to a bright incandescent light.
  2. Connect a DMM from the LCM connector C2 terminal A5 (WHT) to ground.

Is the resistance less than the specified value?

23K ohms

Go to Step 6

Go to Step 11

6

Replace the LCM. Refer to Lamp Control Module Replacement .

Is the repair complete?

--

Go to Headlight System Check

--

7

Repair the open in CKT 39 (PNK) between the underhood fuse block and the LCM. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Headlight System Check

--

8

Inspect CKT 1783 (PPL) between the LCM and the headlamp switch for an open or a short to ground. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems.

Is CKT 1783 OK?

--

Go to Step 9

Go to Step 14

9

Inspect CKT 351 (BLK/WHT) between the headlamp switch and S213 for an open. Refer to Testing for Continuity in Wiring Systems.

Is CKT 351 OK?

--

Go to Step 10

Go to Step 14

10

Replace the headlamp switch.

Is the repair complete?

--

Go to Headlight System Check

--

11

Inspect CKT 278 (WHT) for an open or a short to ground. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems.

Is CKT 278 OK?

--

Go to Step 12

Go to Step 14

12

Inspect CKT 351 (BLK/WHT) between the ambient light sensor and S213 for an open. Refer to Testing for Continuity in Wiring Systems.

Is CKT 351 OK?

--

Go to Step 13

Go to Step 14

13

Replace the ambient light sensor. Refer to Defroster Grille Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

--

Go to Headlight System Check

--

14

Repair the faulty wiring. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Headlight System Check

--